This paper presents an improved genetic algorithm to solve the materialized view selection problem under query cost constraints. The algorithm dynamically changes the crossover probability and mutation probability in the process of genetic. In this way, it can not only maintain the population diversity, but also ensure the convergence of the genetic algorithm. So it effectively improves the opt...

The article deals with the problem of rise in 1950s – first half 1960s, context formation idea Soviet Ukraine philosophy Western world, image Kyiv philosophical school as a prominent participant international scientific process Cold War era. This emerged during Khrushchev’s “thaw” or stage metamorphosis USSR from Stalinism to neo-Stalinist stagnation, namely between XX (1956) and XXIV (1971) Co...

We use a lattice-Boltzmann based Brownian dynamics simulation to investigate the elongation of DNA at a convergent stagnation point trapped by a uniform attractive potential. The trapping rate of the DNA is not sensitive to the potential and, consistent with a mean field theory, scales as the Peclet number, Pe(1/3) . Surprisingly, we find that the coiled state is favored over the stretched stat...

Several authors have claimed that radiocarbon dates in the Ancient Near East are too early. Herein, a hypothesis that might explain this is presented. Marine degassing of “old” carbon (i.e. 14C-deficient C), induced by upwelling of old subsurface water, has been observed, in modern times, to cause century-scale 14C ages in the surface atmosphere. A review of the Mediterranean Sea post-ice-age c...

This paper proves the decidability of several problems in the theory of HD0L, D0L and PD0L systems, some of which that have been proved before but are now proved in a different way. First, the paper tackles the decidability of the nilpotency of HD0L systems and the infinitude of PD0L languages. Then, we prove the decidability of the problem of momentary stagnation of the growth function of PD0L...

The tail of the particle swarm optimisation (PSO) position distribution at stagnation is shown to be describable by a power law. This tail fattening is attributed to particle bursting on all length scales. The origin of the power law is concluded to lie in multiplicative randomness, previously encountered in the study of first-order stochastic difference equations, and generalised here to secon...

Antnet is an agent based routing algorithm based on real ants' behavior. Ants are able to find shortest path to food source .In real life, ants drop some kind of chemical substances to mark the path that they used. Then on their way back they choose the path with the highest pheromones which becomes the shortest path. But Antnet Algorithms may cause the network congestion and stagnation. Here, ...

In order to control the growth of human population it is helpful to understand correctly the mechanism of growth, and the first essential step is to investigate current interpretations and reject any unscientific explanations. One of such popular but questionable interpretations is the concept of the Epoch of Malthusian Stagnation. We discuss its origin, narrative and claims. We explain why thi...

v  Abstract—The mixed convection stagnation point flow toward a vertical plate is investigated. The external flow impinges normal to the heated plate and the surface temperature is assumed to vary linearly with the distance from the stagnation point. The governing partial differential equations are transformed into a set of ordinary differential equations, which are then solved numerically usi...

Three-dimensional molecular dynamics simulations are conducted to study the nanometric cutting of germanium. The phenomena of extrusion, ploughing, and stagnation region are observed from the material flow. The uncut thickness which is defined as the depth from bottom of the tool to the stagnation region is in proportion to the undeformed chip thickness on the scale of our simulation and is alm...